Hi,

I found a solution.

I added a class which handles tha FormSavingNotification. This will add fields defined in my appsettings. Ex.: "DefaultFormTrackingValues": "gclid:[@gclid],utmsource:[@utmsource],sideUrl:[Url],test1:[@test1],test2,test3:[@test3],test4,test5"

If we on a form find any field, that also exist in the list, it adds the missing ones from the list in the same group as the existing.

If we dont find any fields from the list, its creates a new group and add the fields from the list.

The values in the brackets, is the value for the field.

using System;
using System.Collections.Generic;
using System.Linq;
using Umbraco.Cms.Core.Events;
using Umbraco.Forms.Core.Models;
using Umbraco.Forms.Core.Services.Notifications;
using website.core;
using Form = Umbraco.Forms.Core.Models.Form;
namespace Website.Core.Forms.Handlers
{
    public class FormSavingNotificationHandler : INotificationHandler<FormSavingNotification>
    {
        private AppSettings _appSettings;
        private string DefaultFormTrackingValues = "";

        public FormSavingNotificationHandler(AppSettings settings)
        {
            _appSettings = settings;
        }

        /// <summary>
        /// Handles the FormSavingNotification event and performs tracking logic based on the specified appSettings.
        /// </summary>
        /// <param name="notification">The FormSavingNotification object.</param>
        public void Handle(FormSavingNotification notification)
        {
            //Handle Tracking: Handle values speficied in appSettings
            DefaultFormTrackingValues = _appSettings.DefaultFormTrackingValues;
            List<string> neededFieldsWithValues = DefaultFormTrackingValues.Split(',').ToList();
            var requiredFields = DefaultFormTrackingValues.Split(',').Select(val => val.Split(':')[0]).ToList();          
            var hasTracking = false;

            foreach (Form form in notification.SavedEntities)
            {
                //Form with existing group for tracking
                List<KeyValuePair<int, int>> existingFieldSets = new List<KeyValuePair<int, int>>();

                List<string> eistingFieldsOnExistingTracking = new List<string>();
                var pageIndex = 0;

                foreach (Page page in form.Pages)
                {
                    var fieldsetIndex = 0;
                    foreach (FieldSet fieldset in page.FieldSets)
                    {
                        foreach (FieldsetContainer fieldsetContainer in fieldset.Containers)
                        {
                            foreach (Field field in fieldsetContainer.Fields)
                            {
                                if (requiredFields.Contains(field.Alias))
                                {
                                    var key = new KeyValuePair<int, int>(pageIndex, fieldsetIndex);
                                    if (!existingFieldSets.Contains(key))
                                    {
                                        existingFieldSets.Add(key);

                                        hasTracking = true;
                                    }
                                }
                                eistingFieldsOnExistingTracking.Add(field.Alias);
                            }
                        }
                        fieldsetIndex++;
                    }
                    pageIndex++;
                }

                if (hasTracking && existingFieldSets != null)
                {
                    var existingPage = existingFieldSets[0].Key;
                    var existingFieldSet = existingFieldSets[0].Value;

                    //Create missing required fields on existing group
                    var newFields = requiredFields.Except(eistingFieldsOnExistingTracking).ToList();
                    var addToContainer = form.Pages[existingPage].FieldSets[existingFieldSet];
                    CreateFields(newFields, addToContainer.Containers[0]);
                }

                //Form with no group for tracking
                if (!hasTracking)
                {
                    var pagesCount = form.Pages.Count;

                    //if form dosn´t have any of the required fields and dosn't have a group for them
                    FieldSet newContainer = new FieldSet();
                    FieldsetContainer newFieldsetContainer = new FieldsetContainer();

                    newContainer.Caption = "Query Strings";
                    newContainer.Containers.Add(newFieldsetContainer);
                    form.Pages[pagesCount - 1].FieldSets.Add(newContainer);
                    CreateFields(requiredFields, newFieldsetContainer);
                }
            }
        }

        private void CreateFields(List<string> requiredFields, FieldsetContainer newFieldsetContainer)
        {
            foreach (string f in requiredFields)
            {
                var ipGuid = Guid.NewGuid();
                Field newfield = new Field();
                newfield.Alias = f;
                newfield.Caption = f;
                newfield.FieldTypeId = Guid.Parse("0bca0f8f-7ed9-48a0-8693-bc5c204b3130");
                newfield.Id = ipGuid;
                newfield.Mandatory = false;

                if (GetValue(DefaultFormTrackingValues, f) != "")
                {
                    newfield.Settings.Add("DefaultValue", GetValue(DefaultFormTrackingValues, f));
                }
                newFieldsetContainer.Fields.Add(newfield);
            }
        }

        private string GetValue(string input, string searchValue)
        {
            int startIndex = input.IndexOf(searchValue);
            if (startIndex == -1)
            {
                return string.Empty;
            }

            int semicolonIndex = input.IndexOf(':', startIndex);
            if (semicolonIndex == -1)
            {
                return string.Empty;
            }

            int commaIndex = input.IndexOf(',', semicolonIndex);
            if (commaIndex == -1)
            {
                commaIndex = input.Length;
            }

            return input.Substring(semicolonIndex + 1, commaIndex - semicolonIndex - 1);
        }
    }
}

is working on a reply...